[Gasification] Dioxins ...was Clean air ..

Sun Jun 29 19:03:24 CDT 2014

 James,?
	We have had extensive testing done or dioxins on MSW/RDF gasification and in the critical critical areas, did not ?have detectable levels. The third party work was done by Los Alamos National Labs, San Diego's consortium of waste management, ?Sandia National Laboratories and Radian, the same technician/engineer for Radian that prepared an exhaustive analysis for DOE that was the technical basis for US ?EPA to try to get refinery waste gasification exempted from RCRA, but hasn't happened yet.?
	A technical evaluation of gasification shows that without oxygen the basic reaction of Cl+O2->ClO2 doesn't occur and hydrogen will strip the O2 from chlorine compounds already formed, preventing he dioxin formation and breaking down any dioxins introduced to the system. This has been discussed here before.?
	?A GC cannot be used for metal analysis, at least none of the ones I have been exposed to.?
	Not using a qualified technician may allow the regulators to throw out the results.?
	?
Sincerely,
Leland T. "Tom" Taylor
Thermogenics Inc.?

-----Original Message-----
From: James Joyce <james at jamesjoyce.com.au>
To: gasification <gasification at lists.bioenergylists.org>
Sent: Sun, Jun 29, 2014 2:49 am
Subject: Re: [Gasification] Dioxins ...was Clean air ..

Leland, regarding costs. I have had two scenarios described to me, one where the  
sample device is provided and I take the sample (therefore up to me to make that  
representative) and one where a technician comes in to collect the sample. I  
believe the $3000 applies to the first case ... ie. sampling is an additional  
cost. 

If you are referring to on-line or at-line GS-MS or Gel chromatography I am  
interested to hear about experiences with these techniques. Our plant operators  
are not qualified instrument techs or lab techs ... which means at best the  
devices would get a check over on a monthly basis during scheduled plant visits. 

My interest in the bag filter was with respect to particulates. This relates to  
dioxin in that they tend to be adsorbed onto the particulates (although perhaps  
more so at <300 deg C than 600 deg C), so it is one way to remove dioxins and  
their precursors if they are present. Some plants I understand actually inject  
fine carbon into their flue gas for this very purpose. 

Kevin, on your comments about Chlorine and copper, I have been maintaining a  
watching brief for some time on the topic and from what I understand Chlorine  
levels are in fact poorly correlated with Dioxin emissions, arguably because the  
chlorine levels in most feedstocks, even at ppm levels are many many times the  
quantity needed to make the tiny amounts of Dioxins that regulators are checking  
for.  I read a very good review of the science just last week. If anyone wants  
the reference I could dig it out next week. The review of a looked critically at  
a variety of data on Dioxin formation and control. My interpretation of the  
their conclusions is that Dioxin emissions from pyrolysis, gasification and  
combustion processes are: 

(a) Very poorly correlated with Chlorine levels, with the exception of a few  
industrial chemicals (not biomass) 

(b) Strongly correlated to completion of combustion and the residence time of  
flue gases between 200 - 400 deg C (the desired residence times in this range  
were less than 1.6 seconds ...which perhaps does not bode well for torrefaction  
! ... and hot running electrostatic precipitators) 

(c) Catalysed by copper and copper compounds .. which in turn are inhibited by  
the presence of sulphur. 

(d) Sometimes dictated by the dioxin content of the incoming feedstock rather  
than formation in the process 

If anyone has done Dioxin measurements on flue gases from thermal processing of  
biomass I certainly would be interested in their experiences. 

Regards, 

James 

------------------------------ 
Date: Sat, 28 Jun 2014 05:50:23 -0400 (EDT) 
From: linvent at aol.com 
To: gasification at lists.bioenergylists.org 
Subject: Re: [Gasification] Clean Air Regulation requirements imposed 
Message-ID: <8D160CD84083CAD-2D78-1FDBC at webmail-m285.sysops.aol.com> 
Content-Type: text/plain; charset="us-ascii" 

 James, 
	The price you stated for a dioxin test is just the analysis and does not  
include the technician's travel time, set up time and sampling time, per US  
costs.? 
	There is a method of on-stream continuous measurement that will give analysis  
of all of the compounds presented in the standard you referenced that will also  
include fixed gases to almost any molecular weight.? 
	I can't see how any bag or filter can be used to clean the gas.? 

Sincerely, 
Leland T. "Tom" Taylor 
Thermogenics Inc.? 

Date: Sat, 28 Jun 2014 09:22:55 -0300 
From: "Kevin" <kchisholm at ca.inter.net> 
To: "Discussion of biomass pyrolysis and gasification" 
	<gasification at lists.bioenergylists.org> 
Subject: Re: [Gasification] Clean Air Regulation requirements imposed 
Message-ID: <CE1F1C69726943FCAC3E73C36F829823 at usera594fda0bf> 
Content-Type: text/plain; format=flowed; charset="iso-8859-1"; 
	reply-type=original 

Dear James 

It is my understanding that if Chlorine is present in a "biomass pyrolysis  
situation", the presence of dioxins is virtually guaranteed. 

For example, if yak or cattle dung, chicken or feedlot manure, or salt water  
driftwood are pyrolysed or partially burned, there will be dioxins in the  
resulting pyrolysis gases or smoke. 

QUANTITATIVE testing for dioxins could be very expensive, as you suggest.  
However, QUALITATIVE testing can be very low cost. Simply heat a copper wire  
red hot in the presence of the gas being tested for dioxins, when chlorine  
gas or chlorofluorocarbon refrigerants are known to be absent. If dioxins  
are present, the flame turns green or blue-green. 

Best wishes, 

Kevin 

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